GROUPING OF TARGET SEQUENCES FOR CONSCIOUS REPORT

  • Chie Nakatani
  • Cees van Leeuwen

Abstract

A single target presented in a sequence of non-target items (distracters) is detected easily, even when each item is presented less than 100 ms. However, when the number of targets is increased to two, the second one becomes hard to detect. In particular, the second target (T2) is often missed when it is followed by a distracter and the lag from the first target (T1) is 200-500 ms (i.e., attentional blink). However, paradoxically, when T2 is presented just after T1, T2 is often successfully reported (i.e., Lag-1 sparing). A possible explanation of Lag-1 sparing is t hat T1 and T2 are grouped due to their adjacency in time.. We considered this explanationo against the alternative hypothesis that both targets are separately encoded and submitted to working memory. As a neural measure of such processes, we took cross-lag EEG phase synchronization. The results suggest that Lag 1 sparing involves grouping at the item level, while attentional blink is caused by lack of consolidation at the individual item level.

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